This invention relates in general to binocular microscopes. The invention provides a binocular microscope structural arrangement including a detachable optical deflecting unit which can be attached for use in an inclined observation or detached for straight observation.
During ophthalmic surgery, a patient is in a lying down position with the eye being operated on facing "up". Preferably, an ocular lens axis of a binocular microscope, used to assist the surgeon, is inclined with respect to an objective lens axis so that the binocular microscope may be provided with an inclined binocular tube unit.
In otorhinolaryngologic surgery, neurosurgery or plastic surgery, however, an ocular lens axis of a binocular microscope is preferably aligned with that of the objective lens.
Accordingly, in order for a binocular microscope to be used for both types of surgeries, i.e. both inclined and straight observations, conventionally it is provided with an inclined binocular tube unit in addition to a straight binocular tube unit, or a variable optical axis type of a binocular lens unit.
The conventional binocular microscope has disadvantages in that, although an optical system of the inclined binocular lens unit is identical in configuration to that of the straight binocular lens unit, they can never be used in common. Also, the variable optical axis type of the binocular lens unit includes complicated optical elements and mechnical components making it expensive to manufacture.